The present invention is particularly suited to be used as a paintball marker. Paintball is a sport in which players attempt to mark their opponents by using a gun to shoot a frangible projectile. Upon contact with an opponent and sufficient trauma to rupture the frangible outer shell, paint or other marking material shall identify that the opponent player has been hit, and should be removed from the game.
Examples of paint ball marker guns are shown and described in U.S. Pat. No. 7,509,953 to Wood, and U.S. Publications Nos. 2007/0028909, 2007/0151549 and 2011/0088675 to Wood; and U.S. Publication No. 2009/0101129 to Wood et al., the entire contents of which are all incorporated full herein by reference.
Launchers are most commonly pneumatic launching devices fitted with a compressed air or liquid CO2 propellant source. Commonly, launchers generally meter out gas to the ball either by using a valve that is normally closed and contacted by a reciprocating assembly to open said valve for a very short duration. Alternately, launchers may meter out gas by only allowing a fixed volume to be exposed to the ball, removing the requirement of exchanging kinetic energy from a reciprocating assembly to the valve. Oftentimes, this strategy is employed with launchers that utilize a seal that slides open to expose the projectile to gas.
Reference is made to US Patent Publication 2007/0028909 to Wood which is directed to a paintball gun with a specific mechanism for controlling the velocity of a projectile or ball. In this disclosure, the gun has a rangefinder in communication with a microprocessor to calculate the distance between the gun and the target. When the trigger is pulled, the microprocessor notes the current range to the target and directs a solenoid to allow compressed gas to pass through it to a channel for a certain time corresponding to the distance of the target. The shorter duration at the solenoid drives the piston forward, the less compressed gas enters the firing chamber to file the ball. Less compressed gas results in a slower projectile velocity meaning that the projectile will only travel toward a closer target.
U.S. Pat. No. 7,509,953 to Wood is directed to a paintball gun configured to eliminate or reduce recoil by the bolt and firing plunger coaxially moving in opposite directions to minimize recoil. In addition, the pneumatic launching assembly is self-timed to avoid misfiring. The pneumatic launching assembly also provides isolation of gas to improve overall efficiency of the assembly. In operation, the trigger mechanism initiates the launch operation. Upon actuation, gas moves the bolt from its rearward position to a forward launching position after a projectile has been loaded. While the bolt is actuated forward, the projectile is moved into the launching position in the barrel. The bolt then moves forward under control of the gas by directing compressed gas to the rear of the bolt. The firing plunger moves rearward in a coaxially opposed direction of the bolt to minimize recoil. As the firing plunger continues to move rearward, the firing plunger controls the flow of gas. Once the plunger is sufficiently rearward, the front end of the first chamber is breached which allows gas to move from the first chamber into a second chamber in order to actuate the bolt and urge it forward. When the bolt is fully forward, the projectile feeding tube is blocked and the second chamber opens to release gas to propel the projectile forward and out of the barrel. Once the gas isolated in the chamber has been released through the bolt, the firing plunger returns to the forward position as the bolt returns to the rear position. This coaxial movement of the bolt and the firing plunger, i.e., moving in opposite directions, minimizes recoil.
Typically, launchers that include a valve opened by kinetic energy have very low propellant consumption (“high efficiency”), but create more noticeable recoil to players. Launchers that employ the alternative strategy of sliding open a valve and allowing a fixed volume of air to be exposed to the ball generally create a more stable platform for launching due to decreased felt recoil, but have higher consumption rates of propellant and are therefore not as efficient.
In addition to the desired features of a stable launching platform and high gas efficiency, launchers must be able to load and accelerate the most frangible possible marker projectiles to a consistent velocity. Because the indication of elimination in the game of paintball requires the marker projectile to fracture and distribute its contents onto the opposing players to be considered a hit, it is advantageous to subject the projectile to as little stress as possible during loading and acceleration.
The ability to accelerate the projectile to a consistent velocity is desirable, because shots will be measured for velocity before and after competitive games by a chronograph. Shots that are higher than a predetermined velocity limit, typically 300 feet per second, may incur penalties to the players using a launcher that shoots over the velocity limit. By providing a launcher that has a low standard deviation for velocity, players may adjust their mean velocity very close to the limit, providing more initial kinetic energy for the projectile to fracture upon contact with opponents at long range. Thus, the probability of marking success is contingent upon imparting the most possible kinetic energy into the most fragile projectile possible, without breaking the projectile within the launcher itself. Breakage inside the launcher is highly disadvantageous, because the liquid contents of the projectile coat the assembly and barrel inner surface, creating an increased possibility of more projectile breaks, as well as decreasing the accuracy and precision of the projectile due to aerodynamic effects from liquid paint on the projectile in flight.